Process for the production of polyol-alkali metal silicate emulsion

ABSTRACT

A stable polyol-alkali metal silicate emulsion is produced by mixing an aqueous solution of an alkali metal silicate or alkali metal metasilicate pentahydrate, a liquid polyol and a small amount of an acid while heating the mixture to 40° to 100° C. and agitating until the mixture emulsifies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of my copending U.S. patentapplication Ser. No. 146,474 filed May 5, 1980.

BACKGROUND OF THE INVENTION

This invention relates to a process for the production of a stableliquid polyol-alkali metal silicate emulsion by mixing an aqueoussolution of an alkali metal silicate or alkali metal metasilicatepentahydrate, a liquid polyol and a small amount of an acid, preferablean organic acid while heating to 40° to 100° C. and agitating themixture until it emulsifies.

An unstable polyol-alkali metal silicate emulsion can be produced bymixing the liquid polyol and alkali metal silicate while heating andagitating but is unstable and within a few hours the alkali metalsilicate settles to the bottom. The mixture must be re-heated in orderto get the alkali metal silicate into an emulsion with the polyol. Ihave discovered that a stable emulsion of liquid polyol and alkali metalsilicate can be produced by adding 1% to 5% by weight, percentage basedon the alkali metal silicate, of an acid, preferably a polycarboxylcompound. These emulsions are stable for months then when some alkalimetal silicate settle out it is easily re-emulsified by agitating.

A stable liquid polyol-alkali metal silicate emulsion is produced byemulsifying the following components:

Component (a) a liquid alkali metal silicate

Component (b) a liquid polyol

Component (c) an organic acid

Component (a)

Any suitable alkali metal silicate may be used in this invention such assodium, potassium and lithium silicates. The alkali metal silicate arepreferred to be in an aqueous solution which contains 40% to 70% alkalimetal silicate or an alkali metal metasilicate pentahydrate which meltsto form a liquid at a temperature below 100° C. When a solution ofsodium silicate commonly known as "water glass" is used it is necessaryto add an alkali metal hydroxide in the amount up to 10% by weight,percentage based on "water glass", to avoid coagulation of the alkalimetal silicate when added to the polyol. Any suitable alkali metalhydroxide such as sodium hydroxide, potassium hydroxide and mixturesthereof may be used for this purpose.

Component (b)

Any suitable liquid polyol (organic polyhydroxyl compound), inparticular, compounds which contain from 2 to 8 hydroxyl groups,especially those with a molecular weight of about 400 to about 6,000,e.g. polyesters, polyethers, polythioethers, polyacetals, polycarbonatesor polyester amides containing at least 2, generally form 2 to 8, butpreferably dihydric alcohols, with the optional addition of trihydricalcohols, and polybasic, preferably dibasic, carboxylic acids. Insteadof the free polycarboxylic acids, the corresponding polycarboxylic acidanhydrides or corresponding polycarboxylic acid anhydrides orcorresponding polycarboxylic acid esters of lower alcohols or theirmixtures may be used for preparing the polyesters. The polycarboxylicacid may be aliphatic, cycloaliphatic, aromatic and/or heterocyclic andmay be substituted, e.g., with halogen atoms and may be unsaturated;examples include: succinic acid, adipic acid, sebasic acid, subericacid, azelaic acid, phthalic acid, phthalic acid anhydride, isophthalicacid, tetrahydrophthalic acid anhydride, trimellitic acid,hexahydrophthalic acid anhydride, tetrachlorophthalic acid anhydride,endomethylene tetrahydrophthalic acid anhydride, glutaric acidanhydride, fumaric acid, maleic acid, maleic acid anhydride, dimeric andtrimeric fatty acid such as oleic acid, optionally mixed with monomericfatty acids, dimethylterephthalate and bisglycol terephthalate. Anysuitable polyhydric alcohol may be used such as, for example, ethyleneglycol; propylene-1-2 and -1,3-glycol; butylene-1,4- and -2,3-glycol;propylene-1,2- and -1,3-glycol; butylene-1,4- and -2,3-glycol;hexane-1,6-diol; octand-1,8-diol; neopentyl glycol;cyclohexanedimethenol-1(1,4-bis-hydroxymethylcyclohexane);2-methylpropane-1,3-diol; glycerol: trimethylol propane;pentaerythritol; quinitol; mannitol and sorbitol; methyl glycoside;diethylene glycol; triethylene glycol; tetraethylene glycol;polyethylene glycols; dipropylene glycol; polypropylene glycols;dibutylene glycol and polybutylene glycols. The polyesters may alsocontain a proportion of carboxyl end groups. Polyesters of lactones,such as ε-caprolactone, or hydroxycarboxylic acid such asω-hydroxycaproic acid, may also be used.

The polyethers with at least 2, generally from 2 to 8 and preferably 2or 3, hydroxyl groups used according to the invention are known and maybe prepared, e.g., by the polymerization of epoxides, e.g., ethyleneoxide, propylene oxide, butylene oxide, tetrahydrofurane oxide, styreneoxide or epichlorohydrin, each with itself, e.g., in the presence ofBF₃, or by addition of these epoxides, optionally as mixtures orsuccessively, to starting components which contain reactive hydrogenatoms such as alcohols or amines, e.g., water, ethylene glycol;propylene-1,3- or -1,2-glycol; trimethylol propane;4,4-dihydroxydiphenyl propane, aniline, ammonia, ethanolamine orethylenediamine; sucrose polyethers such as those described, e.g., inGerman Auslegeschriften Nos. 1,175,358 and 1,064,938, may also be usedaccording to the invention. It is frequently preferred to use polyetherswhich contain predominantly primary OH groups (up to 90% by weight,based on the total OH groups contained in the polyether). Polyethersmodified with vinyl polymers such as those which may be obtained bypolymerizing styrene or acrylonitrites in the presence of polyethers,(U.S. Pat. Nos. 3,383,351; 3,304,273; 3,523,093 and 3,110,695; andGerman Pat. No. 1,152,536) and polybutadienes which contain OH groupsare also suitable.

By "polythioethers" are meant, in particular, the condensation ofthiodiglycol with itself and/or with other glycols, dicarboxylic acids,formaldehyde, aminocarboxylic acids or amino alcohols. The productsobtained are polythio-mixed ethers or polythioether ester amides,depending on the co-component.

The polyacetals used may be, for example, the compounds which may beobtained form glycols, 4,4'-dihydroxydiphenylmethylmethane, hexanediol,and formaldehyde. Polyacetals suitable for the invention may also beprepared by the polymerization of cyclic acetals.

The polycarbonates with hydroxyl groups used may be of the kind, e.g.,which may be prepared by reaction diols, e.g., propane-1, 3-diol;butane-1, 4-diol; and/or hexane-1,6-diol or diethylene glycol,tiiethylene glycol or tetraethylene glycol, with diarylcarbonates, e.g.,diphenylcarbonates or phosgene.

The polyester amides and polyamides include, e.g., the predominantlylinear condensates obtained from polyvalent saturated and unsaturatedcarboxylic acids or their anhydrides, any polyvalent saturated andunsaturated amino alcohols, diamines, polyamines and mixtures thereof.

Polyhydroxyl compounds which contain urethane or urea groups, modifiedor unmodified natural polyols, e.g., castor oil, carbohydrates andstarches, may also be used. Additional products of alkylene oxides withphenol formaldehyde resins or with urea-formaldehyde resins are alsosuitable for the purpose of the invention.

Examples of these compounds which are to be used according to theinvention have been described in High Polymers, Volume XVI,"Polyurethane, Chemistry and Technology", published by Saunders-FrischInterscience Publishers, New York, London, Volume I, 1962, pages 32 to42 and pages 44 to 54, and Volume II, 1964, pages 5 and 16 and pages 198and 199; and in Kunststoff-Handbuch, Volume VII, Vieweg-Hochtlen,Carl-Hanser-Verlag, Munich, 1966, on pages 45 to 71.

Component (c)

Any suitable organic acid may be used in this invention, such asaliphatic carboxylic acids, aliphatic acid anhydrides, aliphaticpolycarboxylic acids, cycloaliphatic carboxylic acids, cycloaliphaticpolycarboxylic acids, aromatic carboxylic acid, aromatic polycarboxylicacids, heterocyclic polycarboxylic acids, aliphatic carboxylic acidanhydrides, aromatic carboxylic acid anhydrides and mixtures thereof.The organic acids may be substituted, e.g., with halogen atoms and maybe unsaturated.

Organic polycarboxylic acids are preferred. Adipic acid is the preferredpolycarboxylic acid. It is preferred to use the organic mono-carboxylicacids with polycarboxylic acids.

Examples of suitable aliphatic acids are, but are not limited to, aceticacid propionic acid, formic acid, butyric acid, valeric acid, caproicacid, undecanoic acid, lauric acid, palmitic acid, stearic acid, etc.

An example of suitable aliphatic acid anhydrides is acetic anhydride,but examples are not limited to that.

Examples of suitable aromatic acids are, but are not limited to, benzoicacid, para-aminobenzoic acid, salicylic acid, methyl salicylate, etc.

The polycarboxylic acid may be aliphatic, cycloaliphatic, aromaticand/or heterocyclic and may be substituted, e.g., with halogen atoms andmay be unsaturated; examples include: succinic acid, adipic acid,sebacic acid, suberic acid, azelaic acid, phthalic acid, phthalic acidanhydride, isophthalic acid, tetrahydrophthalic acid anhydride,trimellitic acid, hexahydrophthalic acid anhydride, tetrachlorophthalicacid anhydride, endomethylene tetrahydrophthalic acid anhydride,glutaric acid anhydride, fumaric acid, maleic acid, maleic acidanhydride, dimeric and trimeric fatty acid such as oleic acid,optionally mixed with monomeric fatty acids, dimethylterephthalate andbis-glycol terephthalate.

The stable polyol-alkali metal silicate emulsion is useful in theproduction of polyurethane silicate resinous and foamed products. Thepolyol-alkali metal silicate emulsion may be used in the polyurethanefoaming machines which are made to handle a filler in the polyolcomponent, usually called Component (b). The polyol-alkali metalsilicate emulsion, optionally containing an amine catalyst, blowingagent and surface-active agent, is mixed with a polyisocyanate orisocyanate-terminated polyurethane prepolymer and is allowed to react,thereby producing a polyurethane silicate resinous or foamed product.The polyurethane silicate foam and resinous products have many uses,such as for thermal and sound insulation, as light-weight constructionpanels, and as coating agents for wood, metal and plastics.

The polyol-alkali metal silicate emulsion may also be used to producealkali metal polyester silicate resinous products as outlined in U.S.patent application Ser. No. 122,015, filed on Feb. 19, 1980 by David H.Blount, M.D. The polyester alkali metal silicate resinous products maybe used to produce polyurethane silicate resinous and foam products. Theunsaturated alkali metal polyester silicate may be reacted with a vinylmonomer in the presence of a peroxide catalyst to produce solid resinousproducts.

The preferred method to produce polyol-alkali metal silicate emulsion isto mix the polyol and organic acid, then add the alkali metal silicatewhile agitating between ambient temperature and 100° C. at ambientpressure for 10 to 60 minutes, then to cool the mixture while agitating,thereby producing a stable polyol-alkali metal silicate emulsion.

The components may be mixed in any suitable method, such assimultaneously or by mixing any two components first, then adding thethird component last, agitating between ambient temperature and 100° C.for 10 to 60 minutes, then cooling while agitating.

The components may be mixed in any suitable proportions, the preferredproportions being 1 to 50 parts by weight of an aqueous alkali metalsilicate solution to 25 parts by weight of a polyol. Organic acid isadded in the amount of 1% to 5% by weight, percentage based on weight ofthe aqueous alkali metal silicate solution.

The primary object of this invention is to produce stable polyolalkalimetal silicate emulsions. Another object is to produce stablepolyol-alkali metal silicate emulsions which will react withpolyisocyanate compounds to produce useful polyurethane silicate solidand foamed products. Another object is to produce stable polyol-alkalimetal silicate emulsion that will react with polycarboxyl acids andpolycarboxyl acid anhydrides to produce alkali metal polyester silicateresins.

Other components may be added with the components in the production ofpolyol-alkali metal silicate emulsion, especially when the emulsion isto be used to produce polyurethane silicate foam. Any suitable aminecompound may be added, preferably in an amount up to 10% by weight,percentage based on the weight of Components (a), (b) and (c). Tertiaryamines are the preferred amine. Suitable tertiary amines include, butare not limited to, triethylamine, tributylamine, triethylenediamine;N-methyl-morpholine; N,N, N',N'-tetramethylenediamine; triethanolamine;N-methyl-diethanolamine and mixtures thereof.

Up to 1% by weight of organo-metallic compounds may be added withComponents (a), (b) and (c), percentage based on the weight ofComponents (a), (b) and (c), preferably organic-tin compounds such astin salts of carboxylic acid, e.g., tin acetate, tin octoate, tin ethylhexoate, tin laurate and the dialkyl tin salts of carboxylic acids, suchas dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl-tin maleate ordiocyl-tin diacetate.

Up to 20% by weight of a surface-active additive (emulsifiers and foamstabilizers), percentage based on weight of Components (a), (b) and (c),may be added with the Components (a), (b) and (c). Suitable emulsifiersare, e.g., the sodium salts of ricinoleic sulphonates or of fatty acidsor salts of fatty acid with amines, e.g., oleic acid diethylamine orstearic acid diethanolamine. Other surface-active additives are: alkalimetal or ammonium salts of sulphonic acid, e.g., dodecylbenzenesulphonic acid or dinaphthyl methane disulphonic acid; or fatty acidssuch as ricinoleic acid, or polymeric fatty acids. The foam stabilizersused are mainly water-soluble polyester siloxanes. These compoundsgenerally have a polydimethylsiloxane group attached to a copolymer ofethylene oxide and propylene oxide. Foam stabilizers of this kind havebeen described in U.S. Pat. No. 3,629,308.

DESCRIPTION OF PREFERRED EMBODIMENTS

My invention will be illustrated in greater detail in the specificExamples which follow, which detail the preferred embodiment of myprocess. It should be understood that the scope of my invention is notlimited to the specific processes set out in the Examples. Parts andpercentages are by weight, unless otherwise indicated.

EXAMPLE 1

Sodium metasilicate pentahydrate is heated to from 70° C. to 80° C.until the sodium metasilicate pentahydrate melts. About equal parts byweight of the melted sodium metasilicate pentahydrate and polyethyleneglycol (mol. wt. 480), containing 5% by weight of adipic acid and 2% byweight of sodium doctyl sulfosuccinate, are thoroughly agitated untilthe mixture is emulsified, thereby producing a stable polyol-alkalimetal silicate emulsion.

About equal parts by weight of the polyol-alkali metal silicate emulsionand TDI (tolylene diisocyanate) are thoroughly mixed. The mixtureexpands to produce a semi-rigid polyurethane silicate foam which may becut into panels and used for thermal and sound insulation in buildings,automobiles, airplanes, etc.

EXAMPLE 2

About 50 parts by weight of a polyether triol (hydroxyl no. 56), 3 partsby weight of para-aminobenzoic acid, 2 parts by weight of potassiumdoctyl sulfosuccinate and 70 parts by weight of an aqueous sodiumsilicate solution containing 60% sodium silicate with an NaO:SiO₂ ratioof about 1:1.75 are mixed, then heated to about 50° C. while vigorouslyagitating, thereby producing a stable polyol-alkali metal silicateemulsion.

The polyol-alkali metal silicate emulsion may be used to produceflexible foam by mixing 100 parts by weight of the polyol-alkali metalsilicate emulsion, 0.25 part by weight of tin oxalate, 0.25 part byweight of diethylenediamine and 50 parts by weight of TDI; the mixtureexpands to produce a flexible polyurethane silicate foam weighing from 1to 2 pounds/cubic foot. This foam may be used for padding, packaging,cushions, insulation, etc.

EXAMPLE 3

About 50 parts by weight of an amine sucrose polyol (Poly G 71-530produced by Olin), 2 parts by weight of adipic acid, 1 part by weight ofbenzoic acid and 70 parts by weight of sodium metasilicate pentahydrateare mixed, then heated to about 70° C., then agitated for 3 to 10minutes, thereby producing a stable polyol-alkali metal silicateemulsion.

EXAMPLE 4

About 200 grams of polyethylene glycol (mol. wt. 600), 200 grams of anaqueous solution containing 60% sodium silicate (NaO:SiO₂ ratio of about1:2) and 4 parts by weight of adipic acid are mixed and heated to about50° C., then placed into a malt mixing machine and mixed for 1 to 3minutes, thereby producing a stable polyol-alkali metal silicateemulsion.

EXAMPLE 5

A comparison study was done using the same process and components ofExample 4, except that the adipic acid was left out. The mixtureemulsified, but within a few hours, the sodium silicate precipitated andformed a firm mass in the bottom of the container and would notre-emulsify with agitation. The polyol-alkali metal silicate emulsion ofExample 4 remained stable for several months; very little of the sodiumsilicate settled to the bottom after a month and was easily emulsifiedby agitation.

EXAMPLE 6

About equal parts by weight of an aqueous solution, containing 55% byweight of sodium silicate with an NaO:SiO₂ ratio of about 1:1.75, and apolyol listed below was mixed with about 3% by weight of an organic acidlisted below, based on the alkali metal silicate, 2% by weight of sodiumdoctyl sulfosuccinate, based on reactants, 1% by weight of a siliconesurfactant, based on reactant, and 0.5% by weight of triethylenediamine,based on weight of reactants. The mixture was then vigorously agitatedat about 50° C. and continued until the mixture cooled to about 30° C.,thereby producing a stable polyol-alkali metal silicate emulsion.

    ______________________________________                                        Ex-                                                                           AM-                                                                           ple  Polyol              Organic acid                                         ______________________________________                                        a    Ethylene glycol (mol. wt. 380);                                                                   Phthalic acid;                                       b    Ethylene glycol (mol. wt. 600);                                                                   Phthalic anhydride;                                  c    Ethylene glycol (mol. wt. 1000)                                                                   Equal parts benzoic acid                                  with equal parts of propyl-                                                                       and adipic acid;                                          ene glycol (mol. wt. 600);                                               d    Propylene glycol (mol. wt. 600);                                                                  para-aminobenzoic acid                                                        with equal parts by                                                           weight of acetic acid;                               e    Propylene glycol (mol. wt.                                                                        Equal parts by weight of                                  1200);              adipic acid and propi-                                                        onic acid;                                           f    Castor oil;         Acetic acid;                                         g    Ethylene polyether triol                                                                          Isophthalic acid and                                      (hydroxyl No. 56);  fumaric acid                                         h    Ethylene polyether diol                                                                           Maleic anhydride;                                         (hydroxyl No. 112);                                                      i    Ethylene polyether diol                                                                           Oleic acid;                                               (hydroxyl No. 56);                                                       j    Amine surcose polyether                                                                           Equal parts by weight                                     polyol (hydroxyl No. 350);                                                                        of tetrahlorophthalic                                                         acid anhydride and                                                            fumaric acid;                                        k    Polyester resin (0.5 mol. of                                                                      Equal parts by weight                                     adipic acid and 4 mols of                                                                         of acetic acid and                                        glycerol);          azelaic acid;                                        l    Glycerol;           Glutaric acid anhydride;                             m    Equal parts by weight of                                                                          Equal parts by weight                                     ethylene glycol (mol. wt.                                                                         of adipic acid and                                        380) and starch;    glycolic acid;                                       n    5 parts by weight of ethylene                                                                     w-hydroxycaproic acid                                     glycol (mol. wt. 600) and                                                                         and equal parts by                                        1 part of weight of weight of para-                                           resorcinol;         aminobenzoic acid;                                   o    Equal parts by weight of poly-                                                                    Equal parts by weight of                                  propylene diol (mol. wt. 600)                                                                     adipic acid and                                           and cellulose powder;                                                                             propionic acid;                                      p    Liquid formaldehyde phenol resin                                                                  Equal parts by weight of                                  with free hydroxyl group and                                                                      malic acid and phthalic                                   equal parts by weight of tri-                                                                     acid anhydride;                                           chlorobutylene oxide;                                                    q    Ethylene-propylene polyether                                                                      Adipic acid.                                              diol (hydroxyl no. 33.5).                                                ______________________________________                                    

Although specific conditions and ingredients have been described inconjunction with the above Examples of preferred embodiments, these maybe varied and other reagents and additives may be used, where suitable,as described above, with similar results.

Other modifications and applications of this invention will occur tothose skilled in the art, upon reading this disclosure. These areintended to be included within the scope of this invention as defined inthe appended claims.

I claim:
 1. The process for the production of a stable polyol-alkalimetal silicate emulsion by mixing the following components:(a) Aqueousalkali metal silicate solution, 1 to 50 parts by weight; (b) Polyol, 25parts by weight; (c) Organic acid, 1% to 5% by weight, percentage basedon weight of alkali metal silicate solution.
 2. The process of claim 1wherein the alkali metal silicate is selected from the group consistingof sodium silicate, potassium silicate, lithium silicate and mixturesthereof.
 3. The process of claim 1 wherein the polyol is selected fromthe group consisting of polyhydric alcohol, polyesters, polyethers,polythioethers, polyacetals, polycarbonates, polyester amides containingat least 2 hydroxy groups, and mixtures thereof.
 4. The process of claim1 wherein the organic acid is selected from the group consisting ofaliphatic carboxylic acid, aliphatic polycarboxylic acid, cycloaliphaticcarboxylic acid, cycloaliphatic polycarboxylic acid, aromatic carboxylicacid, aromatic polycarboxylic acid, heterocyclic polycarboxylic acid,aliphatic carboxylic acid anhydrides, aromatic carboxylic acidanhydrides and mixtures thereof.
 5. The process of claim 1 wherein theorganic acid is adipic acid.
 6. The product produced by the process ofclaim
 1. 7. The process of claim 1 wherein an amine compound in theamount of up to 10% is added with Components (a), (b) and (c).
 8. Theprocess of claim 1 wherein the amine compound is a tertiary amine. 9.The process of claim 1 wherein up to 20% by weight of an emulsifyingagent is added to the Components (a), (b) and (c), percentage based onweight of Components (a), (b) and (c).
 10. The process of claim 1wherein up to 20% by weight of a foam stabilizer, percentage based onComponents (a), (b) and (c), is added with Components (a), (b) and (c).